The invention relates to a suction device for fluids, especially on water needling machines, to which device a water manifold for generating fluid jets is attached, possibly consisting of a suction tube with suction holes arranged over the working length of the tube, through which holes the fluid is extracted by a partial vacuum generated in the tube, and wherein slide strips are arranged on both sides and parallel to the holes to support a transport means, such as a perforated drum, for the web-like material to be needled. Because of the partial vacuum to be generated between 20 mbar and 400 mbar, the fixed suction tube must be of an extremely robust design. The suction tubes are therefore drilled into a rigid tube. The slide strips for the drum transporting the material are then fixed laterally relative to these openings, which strips define the suction slit.
A suction device of this type is described in European Patent EP-A-1 059 377. Not only water but also a large quantity of fiber or pulp, depending on the material to be dewatered, is forced by the suction tube through the suction slit or suction openings of the suction tube. An unavoidable phenomenon is that not only the suction strips or webs between the suction openings but also the interior surface of the suction tube become contaminated and must be cleaned to ensure a uniform dewatering effect. Previously, in order to accomplish this, the front end of the tube had to be disassembled and exposed so as to make the interior surface of the tube accessible for cleaning.
This condition is also not remedied by the cleaning device, known from European Patents 0 853 156 or 0 088 859, which is provided for the cleaning of the perforated drum. In this design, a cleaning tube extends through the front side, through the shaft of the drum carrying the material, from the openings of which tube water is sprayed against the drum, the openings being directed at the interior surface of the drum.